Preparation Of Herirarchical ZSM-5 Zeolite Based On Nanocellulose Template And Its Catalytic Pyrolysis Of Waste Plastics

In recent years,environmental pollution caused by waste plastics has become increasingly serious.Waste plastics that are difficult to degrade are still the global "big problem".Traditional methods such as burying and burning are difficult to dispose of a large amount of waste plastics,and will also cause secondary pollution of soil and air.On the other hand,the main elements in waste plastics are carbon and hydrogen,which can be converted into high value-added products through chemical methods,which can achieve a win-win effect:the solution of environmental pollution and the high-value utilization of waste plastics.Therefore,it is an arduous task to transform waste plastics into high value-added chemicals efficiently and safely.In this paper,hierarchical ZSM-5 zeolites were synthesized by using nanocellulose as mesoporous template.The ZSM-5 zeolites prepared by this method showed excellent catalytic performance on fast catalytic pyrolysis of waste plastics(LDPE).The main research results are as follows:(1)Synthesis of hierarchical ZSM-5 zeolites.Hierarchical ZSM-5 zeolites were synthesized by hydrothermal method mesoporous template nanocellulose(NCC)and TPAOH as co-template.XRD,IR,BET,SEM,TEM and other characterizations proved that hierarchical ZSM-5 zeolites modified with nanocellulose has a larger specific surface area,pore volume and pore size,and the particle arrangement is more orderly in morphology.(2)Research the on fast catalytic pyrolysis of LDPE over hierarchical ZSM-5 zeolites.The effects of the four factors of nanocellulose addition,silicon-to-aluminum ratio,temperature and the ratio of waste plastic to catalyst on the catalytic performance were investigated.The results show that the yield of liquid oil increases first and then decreases with the increase of nanocellulose.When the silicon-to-aluminum ratio decreases,the oil yield increases.when the temperature increases,the liquid oil production first increases and then decreases.When the ratio of waste plastics to catalyst increases,the yield of liquid oil first increases and then decreases.Finally,10%NCC-ZSM-5 zeolite obtains the highest oil yield of 71.3%at 450℃and the ratio was 0.5.(3)Study on the catalytic performance of hierarchical ZSM-5 zeolites loaded with metals.In this experiment,10%NCC-ZSM-5 zeolite loaded with different metals(Ni,Nb,Fe,Co)by impregnation method.Experimental results show that metal Ni improves the selectivity of aromatic hydrocarbons and H2.The effects of Ni loading and temperature on the catalytic performance were further investigated.It was found that the selectivity of aromatics and H2 first increased and then decreased with the increase of Ni loading and temperature.Finally,6%Ni-10%NCC-ZSM-5 zeolite has the highest selectivity for aromatics and jet fuel at 475℃,which is 57.3%and 66.8%respectively.